The invention relates to a modular system comprising an electrical base unit with a plurality of slots each for receiving a pluggable electrical unit, each pluggable electrical unit being electrically connected to the base unit by means of a multi-pin plug-in connection comprising a plug-in contact device and a mating plug-in contact device.
Complex electrical engineering systems, in particular in measuring and control technology and in telecommunications, are often of a modular construction. This involves a large number of electrical units being accommodated in an enclosure of an electrical base unit in a pluggable manner.
The base unit is often provided with rear wiring which connects all the mating plug-in contact devices, and may be configured as a cable harness, as a winding bridge or as a backplane. To allow a free choice of the slot for any desired pluggable unit, in this case plug-in contacts of the same name of each mating plug-in contact device are usually connected to one another in the manner of a parallel bus. For this purpose, the pluggable electrical units are of an identical mechanical type of construction and are configured with an identical electrical interface designed for the plug-in contact device.
Such backplane wiring in the manner of a parallel bus no longer allows individualizing of the electrical interface of the pluggable electrical units that is designed for the plug-in contact device, since plug-in contacts of the same name would be wired to different types of signals, which may also differ in the direction of signal transmission. If the free choice of slots is maintained for all the pluggable electrical units, the number of necessary plug-in contacts increases in proportion to the degree of individualization of the pluggable electrical units, and so does the complexity of the backplane wiring. This additional complexity is felt to be disadvantageous. In addition, the overall size of the plug-in connector increases with the number of pins. Plug-in connectors of a larger overall size are at odds with the miniaturization of pluggable electrical units.